Process of burning cement.



PATENTED'JAN'. 29, 1907.

No, 842,848. I

" c. ApMATGHAM.

PROCESS OF BURNING CEMENT.

Arrmgumn rum) DEO.28,1906. v,

rus uoRRls' PETERS cm. w lsuiuc'rou, n c.

CHARLES MATOHAM, OF ALLEN TOWN, PENNSYLVANIA.

' PROCESS OF BURNING CEMENT.

Specification of Letters Patent.

Patented Jan. 29, .1907.

Application as December 28,1906. Serial No. 349,309.

To all whom it mag concerns Be it known that I, CHARLES A. MAToHAM, a citizen of the United States, residing in Allentown, Pennsylvania, have invented certain Improvements in the Processes of Burn ing Cement, of which the following is a speci fication.

My invention relates to certain improvements in the process of burning cement. The object of the invention is to burn the material to be treated more evenly than has heretofore been done and to reduce the deleterious eflect of the flame u on the fire-brick lining by causing the pro nets of combus- I 5 tion to be drawn into the rotary or other kiln by thenatural draft of a chimney, in contradistinction to the usual practice of using a forced draft for thispurpose.

My invention is particularly adapted for use in connection with a rotary kiln employ- -in fuel in the form of finely-pulverized coal. y forcing the fuel into the kiln under ressure I find that either the fuel-feed must I e so regulated as to produce a flame which 2 5 will not impinge upon the interior surface of the kiln or else the material or the burner a must be so arranged that the-flame will im- 'inge upon the surface of the kiln. In the fbrmer case the process is slow, owing to the fact that the material is burned by radiation. In the latter case there is such an intense heat at the point of impingement upon the kiln and the flame strikes the material or the lining of the kiln with such force that the -5 lining is rapidly destroyed and the product is unevenly. burned. Furthermore, the intense heat at this point will overburn the product unless the most careful watch is maintained during the process of burning. 0 By the process hereinafter described I am enabled to more evenly burn the material than heretofore, and as there is no forced draft the lining ofthe'kiln is not subjected to I an impinging flame, the fuel being drawn into 5 the furnace by the natural draft of the stack.

The flame being carried through the kiln by the draft of the stack is caused to pass gently in contact with the material being clinkered, as well as with that from which the carbonic- 5o acid gas is being driven ofl. There is there- In the accompanying drawings, Figure 1 is a vertical section of a rota kiln and stack, illustrating my invention. Fig. 2 is anend elevation of the hood at the discharge end of the kiln. Fig. 3 is an enlarged view of a form of fuel-feeder which I'prefer to use in carrying out. my invention. Fig. 4 is an enlarged sectional View of part of Fig. 3. Fig.

5 is a sectional view on the line 5 5, Fig. 4'; and

Fig. 6 is a view illustrating another form of kiln in which my process may be carried out.

. In the above drawings, A is a rotary kiln of the ordinary type mounted on suitable rollers c c and driven by the ordinary mechanism C. Y B is the back hood, and D is the front hood,

respectively closing the ends of the rotary kiln A. Mounted on the back hood-B is a stack B of such a height and diameter that it will cause a suflicient draft in the kiln as to not only draw the finely-powdered coal into it, but will also produce the desired sliding flame throughout the entire length of thekiln to the stack.

The height and diameter of the stack will var with the varying lengths and diameters of the kiln; but the kilns and stacks must be so pro ortioned. that the natural draft will be s' cient to draw-the powdered coal into the kiln and to produce the desired flame.

I have obtained very good results with a kiln eighty feet long, five feet ei ht inches internaldiameter, having a stac ninety feet high and four feet internal diameter, using a burner as proportioned in the drawings, although the proportions of both kiln and burner may vary with the material under treatment and with the quality of the coal use In the hood D is an outlet at for the mate-. rial, which connects with the passage f, communicating with the pit'F. i

E is an inclined. hute which enters an opening (I in the front hood D, and this chute communicates with a conveyer E, in the 100 present instance consistin of a trough, in which is mounted a screw riven in any suit: able manner for conveying the coal from a bin to the chute in a practically uninterrupted stream. Directly under the chute is a plate 105 c, with an inclined lip e and directl-y'under this plate in the present instance is a plate G, having a beveled-ed eg. This latter plate is ,adjustably mounte on a pivoted frame g.,

F} so that it can be moved to regulate the point i 1 0 water will freely circulate through it, as it,

5 will be understood that this plate may proecome hi hly heated, The fue -feeder is providedvwith air-passages 5,5, and '5 While at each side of said 16 feeder are other air-passages i The flow of air through the passages i and i may be re ulated by suitable dampers as desired.

ythe above-described arrangement the proper volume of air at normal temperature 5 dered coal. This air alone in many instances is not suflicient to produce a proper combustion of the fuel; and. I therefore extend the outlet-opening d to form a deep flue (Z in the lower part of the hood D, said flue extending from the pit-passage f to-a point directly under the fuel-feed opening. This flue allows for a large volume of heated air from the clinker-pit to be drawn into the kiln by the 2 5 natural draft at a oint directly under the incoming powdered e1, so that it mingles with the incoming cool air and bodily supports,

the fuel, producing a perfect flame for the burning of the cement as it passes into and through the kiln. i The construction of the front hood and the fuel-feeding device are fully set forth and claimed in an application for patent filed by me December 31, 1906, Serial No. 350,215, and I therefore lay no claim to the said construction of the hood and burner in the present application. a

The material is fed into the rear end of the kiln through a chute 75, connected to a con- 40 veyer H, preferabl of the screw type, which removes material f fom" a bin H,- situated at any convenient point, it being understood, however, that the'material may be fed into the kiln by any other suitable mechanism.

, It is not necessary that a single-cylinder kilnshould be used in carrying out my invention, as a two-cylinder kiln may be cml .ployed, as shown in Fig. 6 and as set forth inmy application for'patent filed August 22, 190 Serial No; 331,595, without departing from the essential feature of said nvention.

In carrying out my improved process, the

material is fed into the kiln in definite quantities through the chute h while the kiln is; slowlyrotated, and the fuel is fed in given amounts through the chute E, so as to fallin front of the air-inlet openings The natural draft at the stack end of. thekiln will cause drawn-in through the opening d, carrying with it the finely-divided fuel and at the-same time causing a relatively large volume of heated air. to pass. from the pit air to' be .9-

through the .flue dto a -.p0int directly under the fuel iril'etiopening 1.9. A flame will thus 6 5 be immediately produced, .being drawn ect into the furnace to such an extent as to can 'be drawn into the kiln with the powthrough the kiln in a s iral path and having a sliding contact wit the material being treated and with the walls of the kiln. This results in a more even-burningof the materialbeing calcined than by any forced-draft system, and instead of burning out the firebrick lining, as is the tendency of a forceddraft flame, which impinges directly upon the material being treated, it rather avoids such action. r

While I prefer to use a high stack to pro,- duce a natural draft, other means may be used at the stack end of the'kiln to produce an induced draft, and while I have used the term air throughout the specification and claims this must be understood to cover mixed gases or "other gas. I claim 1. The process herein described of burning cement in a substantially horizontal kiln, said process consisting in feeding the cement material into one end of the kiln and allowing it to-fiow from the'inlet end to the discharge end thereof, feeding powdered fuel to the kiln, creating at the'inlet end of the kiln a draft through said kiln from the discharge end to the inlet end thereof sufficient to draw into the kiln the powdered fuel and a volume of air, the flame being drawn in a substantially straight path through the kiln in contact with the cement material without materially disintegrating the lining thereof, substantially as described.

2. The process herein described of burning cement in a substantially horizontal kiln, said process consisting in feeding the cement material into one end of the kiln, creating at the inlet end of the kiln a draft through the kiln from the discharge end-to the inlet'end I thereof, and thereby simultaneously drawing 105 into the discharge end of the as1:r eam of powdered fuel, a volume'of airatinormaltemperature, and a relatively* large" volume of heated air, the flame bein g drawn through without materially disintegrating-the of. the kiln, substantially as; described. f '3. The process herein described of bu: g cement in a substantially horizontal kiln, said process consisting in feeding the cement. material into one-end of the kiln, creatingat the; stack endof the'kiln a draft. through the from the; discharge end to the" stacli v end thereof, drawing into the dischargejend "off: the kiln by said draft-1a stream of-powdere fuel with a volume-of air at normal tempera ture and simultaneously introducing a rela tively larger volumeofheated air directly under the incoming powdered fuel and air, thereby immediately'forming a combustible mixture with the fuel as this enters the kiln, substantially as described. i 4. The process herein describedof burning {cement in a substantially horizontal kiln, f said ,process consisting in creating a draft-at 13o the stack end of the kiln, feeding powdered In testimony whereof. I have signed my fuel in a relatively dense mass directly into name to this specification in the presence of the 'kiln and draw g in a relatively large two subscribing witnesses.

volume of heated air directly under the poW- CHARLES A. MATCHAM. v I

5 dered fuel so as to spread and support said Witnesses:

fuel and carry it into the'combustion zone of 1 WILLIAM E. BRADLEY, the furnace, substantially as described. J 0s. H.' KLEIN: 

